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Old 28-02-2010, 21:04   #196
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I believe that the development of new technology is vital to the modern merchant marine, but we should not forget that even the best technology can fail. The money to upgrade our GPS system and fully implement eLORAN needs to be allocated
sorry but your post is inconsistent, firstly you make the point that Failure of the GPS system would be diasasterous, then you go on to say that ships shoul carry sextants. GPS is such that it will not be allowed to fail. There is also the european system beginning to be deployed, the chineese are doing one and the Russians intend to enhance and complete GLONASS

Secondly stating that all technology can fail as justification for A sextant is ridiculous. A modern ship is all technology. Failure of any system can disable it. Engines for example. Yet we don't expect then to have sails!!. The fact is we live every day with possible tech failure.
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Old 01-03-2010, 09:40   #197
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Originally Posted by goboatingnow View Post
Secondly stating that all technology can fail as justification for A sextant is ridiculous. A modern ship is all technology. Failure of any system can disable it. Engines for example. Yet we don't expect then to have sails!!. The fact is we live every day with possible tech failure.
I think you forget who you are talking to gbn, We do have sails on our boats....
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Old 01-03-2010, 14:42   #198
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The poster alan2 was talking about ships
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Old 03-03-2010, 00:34   #199
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Interestingly or troublingly, it seems that more and more vessels clear port without a sextant, and or the charts, tables that would be used with same, to determine one's position. As I understand, possibly incorrectly, this applies to naval vessels as well as commercial ships.
While I can't speak for the Navy (last I heard is that the USNA has stopped teaching celestial navigation to midshipmen), U.S.-flagged ocean-going merchant ships still very much do carry sextants and all the required publications to go along with it. Celestial Navigation is still taught at the Maritime Academies. How much it's actually used is another matter.

Actually, the most I have ever done Celestial Navigation with a sextant was as a Cadet during my at-sea training and since then (as a licensed officer), the most I've done is when helping a Cadet who is still learning. This actually helps me to stay proficient too, seeing as how we'll do it longhand and check up with the computer at the end.

Now, that being said, while we don't regularly take position fixes using celestial LOPs, celestial azimuths (sun and stars, mainly) are still very much used (in some cases, once per watch) to check for compass error, both gyro and magnetic. If done right, in ideal conditions, it's very accurate - within 0.5 degrees.
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Old 03-03-2010, 01:00   #200
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to check for compass error, both gyro and magnetic
For this we just use the Pelorus and a Sun rise each day, that is if someone is available and remembers, got to keep them logs in order for the surveyors eh....
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Old 03-03-2010, 01:13   #201
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I am wondering about using paper charts with a GPS. I learned to Navigate with costal navigation and like paper charts. I have a plotter and like that as well. Problem is on some paper charts there is no datum reference. So lets say that you get within five miles of a location, using a radar range. You know that there is a rock that you must avoid at 3 miles. There is a lighthouse and an obvious point that you can get a bearing on with a hand bearing compass(HBC). Your chart plotter shows you at three miles. Then you plot your position on the chart using the GPS and it shows you in the same place as the plotter. Then you take out the HBC and find your position. It shows you at 5 miles. Now you have two places where you might be. First thing that I would do is stop and head back on a reciprocal course.

My question:

Are the paper charts going to give you a more accurate position with the HBC?
Absolutely. But that's kind of the same thing as radar overlay on your plotter with similar result at less effort.

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My guess is that the paper charts are going to give you a better idea of your location b/c you are using matching technologies. The HBC and the paper charts.
Well, not better than a plotter used with radar. Better than plotter alone because you've checked your position a second way.

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Using the lat and long of the GPS will give you an accurate location of where you are in the world but not where you are in relation to the chart. Am I right? Has anyone had real world experience with this?
In a word, no.

I have sailed all over the world and I have never used a paper chart without accurate lat & lon marked on it. Are you sure you know how to read this aspect of a maritime chart? I was warned when I went sailing in the Sea of Cortez that the charts (and plotters) are ancient and off by as much as a mile, but constant double-checking with radar and hand bearing compass did not reveal any gross errors, in the area where we were.

The electronic charts on plotters are based on paper charts, and in my experience accumulated in many parts of the world, they are generally equal to each other in accuracy and detail.

Disclaimer: I have never used the very latest generation of electronic charts with photo maps and 3D and all that, so I can't comment on that. Maybe that's a leap forward; maybe it's worse, I just don't know. I use C-Map NT+ electronic charts which are really just digitized paper charts, and I bet most sailors are still using similar electronic charts.

I am a little old fashioned and would never sail anywhere without having paper charts of the area on board and to hand. That's not because they're more accurate, but what would you do if your electronics went down? It would be simply irresponsible, I think.

But l also think that paper charts, although they are not more accurate, are also much better for planning. Spread out on a chart table you get a much better feel and orientation for where you are and where you are going. A chart plotter is a little like a video game -- you get your head down into it and you lose touch with the real world around you. That doesn't happen with paper charts. Even if I don't always refer to them underway, I do always study paper charts before sailing somewhere I don't know well, and study them hard, and always refer to them for general orientation.

I think paper charts are crucially valuble, but others may have a different style of navigation and pilotage.


I'd also mention a word in favor of radar as a navigation aid. I sailed all my whole life without radar, other than brief spells on other people's boats, until we bought our present boat last fall, which has a 4kW 24" Raymarine Pathfinder jobbie on it.

Radar is even better than a hand bearing compass as a navigation aid because, for one thing, it works at night and in fog. Using the EBL, it's a virtual hand bearing compass, but the VRM does in a second what takes a lot of calculation with a hand bearing compass. It's great. I can't now imagine being without it. I somehow had the idea that it is mostly useful for detecting and tracking other vessels; I had no idea how useful it is as a navigation aid and double-check of your plotter.
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Old 03-03-2010, 01:21   #202
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As a unit for mesuring distance the radar has no equal. But using GPS, We use it with paper charts by using the center of a compass rose as a go to point and take the distance and bearing to our possition. But once in site of land we use pilotage as it is safer by using bearings to fixed objects.
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Old 03-03-2010, 01:32   #203
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I can't beleive some of the arguments in this thread...what are you arguing about ?
A navigator must take into account all inputs in making decisions as to course to steer and DR position.
Your GPS plotter is only as accurate as the charts that are loaded into it...so the Paper chart vs plotter argument is no argument at all.
When close to land we use radar and C-Map plotter...we also have MaxSea (raster charts) on board..AND we have the paper chart to hand.
We assimilate all the inputs to try to work out where we are.
That's what's important, not whetehr your GPS or whatever is accurate to 50m , 10 m, whatever...look out the window ..that's where you see where you are.
YOU are the navigator...YOU are responsible for knowing where you are, not some plastic box...I don't care where it comes from

AND YES I do carry a sextant..and I DO use it...for noon sights mostly

We need to have as much informatiuon as possible and back ups for all the backups...
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Old 03-03-2010, 05:27   #204
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While I can't speak for the Navy (last I heard is that the USNA has stopped teaching celestial navigation to midshipmen), U.S.-flagged ocean-going merchant ships still very much do carry sextants and all the required publications to go along with it. Celestial Navigation is still taught at the Maritime Academies. How much it's actually used is another matter
Waterman this is not so

On May 2, 2001, the United States Coast Guard amended the United States chart carriage regulations to permit government vessels to use electronic charting and navigation systems in lieu of paper charts.


On August 15, 2002, the United States Coast Guard issued a statement of policy to bring its regulations into agreement with SOLAS Chapter V (as amended by the changes taking effect July 1, 2002). The policy statement said that, if a ship has an approved ECDIS installed according to SOLAS, Chapter V, the ECDIS will be considered as meeting the ship's nautical chart carriage regulations. The ships that are affected are:
    • U.S.-flagged ships of 150 or more gross tons that engage on international voyages.
    • U.S.-flagged ships certificated solely for service on the Great Lakes and the St. Lawrence River.
    • Foreign-flag ships to which SOLAS, Chapter V, applies that are operating on the navigable waters of the United States.
This policy is not applicable to U.S.-flag ships engaged only on domestic voyages. These ships must continue to comply with existing navigation equipment requirements until the chart carriage regulations are formally amended.

furthermore

The International Maritime Organization mandates the use of GPS or some type of electronic navigation system onboard oceangoing ships, but makes no such requirement for celestial navigation equipmen

Watchkeeping code requires deck officers to show proficiency in celestial navigation — but SOLAS (International Convention for the Safety of Life At Sea) doesn’t require ships to carry a sextant!
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Old 03-03-2010, 10:35   #205
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Originally Posted by Albro359 View Post
I can't beleive some of the arguments in this thread...what are you arguing about ?
A navigator must take into account all inputs in making decisions as to course to steer and DR position.
Your GPS plotter is only as accurate as the charts that are loaded into it...so the Paper chart vs plotter argument is no argument at all.
When close to land we use radar and C-Map plotter...we also have MaxSea (raster charts) on board..AND we have the paper chart to hand.
We assimilate all the inputs to try to work out where we are.
That's what's important, not whetehr your GPS or whatever is accurate to 50m , 10 m, whatever...look out the window ..that's where you see where you are.
YOU are the navigator...YOU are responsible for knowing where you are, not some plastic box...I don't care where it comes from

AND YES I do carry a sextant..and I DO use it...for noon sights mostly

We need to have as much informatiuon as possible and back ups for all the backups...
Well said, I agree completely.
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Old 03-03-2010, 11:34   #206
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Originally Posted by Albro359 View Post
I can't beleive some of the arguments in this thread...what are you arguing about ?
A navigator must take into account all inputs in making decisions as to course to steer and DR position.
Your GPS plotter is only as accurate as the charts that are loaded into it...so the Paper chart vs plotter argument is no argument at all.
When close to land we use radar and C-Map plotter...we also have MaxSea (raster charts) on board..AND we have the paper chart to hand.
We assimilate all the inputs to try to work out where we are.
That's what's important, not whetehr your GPS or whatever is accurate to 50m , 10 m, whatever...look out the window ..that's where you see where you are.
YOU are the navigator...YOU are responsible for knowing where you are, not some plastic box...I don't care where it comes from

AND YES I do carry a sextant..and I DO use it...for noon sights mostly

We need to have as much informatiuon as possible and back ups for all the backups...
yep.
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Old 03-03-2010, 16:49   #207
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While I can't speak for the Navy (last I heard is that the USNA has stopped teaching celestial navigation to midshipmen), U.S.-flagged ocean-going merchant ships still very much do carry sextants and all the required publications to go along with it. Celestial Navigation is still taught at the Maritime Academies. How much it's actually used is another matter.

Actually, the most I have ever done Celestial Navigation with a sextant was as a Cadet during my at-sea training and since then (as a licensed officer), the most I've done is when helping a Cadet who is still learning. This actually helps me to stay proficient too, seeing as how we'll do it longhand and check up with the computer at the end.

Now, that being said, while we don't regularly take position fixes using celestial LOPs, celestial azimuths (sun and stars, mainly) are still very much used (in some cases, once per watch) to check for compass error, both gyro and magnetic. If done right, in ideal conditions, it's very accurate - within 0.5 degrees.
It's one thing to have the learning, the tools and choosing, for any number of reasons, not to use them. Not having the learning and or lacking the equipment is an entirely different story. Electronics can and sometimes do go to hell, especially on small boats, (yachts), where there isn't the depth of redundency found elsewhere.

Finding ones position electronically, with a GPS, is certainly quicker and likely more accurate than via sextant shots and messing about with tables and plotting sheets, however should the electronics go down, an estimated position that's within say 5 NM of where one is, is a whole lot better than nothing I suspect.

Also, speaking personally, and I realize that there is no accounting for taste, I find old fashioned sextant navigation (position finding) to be an interesting intellectual exercise. It also serves to keep the kid out of those smokey pool rooms, assuming that any still exist.
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Old 05-03-2010, 00:27   #208
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Waterman this is not so

On May 2, 2001, the United States Coast Guard amended the United States chart carriage regulations to permit government vessels to use electronic charting and navigation systems in lieu of paper charts.


On August 15, 2002, the United States Coast Guard issued a statement of policy to bring its regulations into agreement with SOLAS Chapter V (as amended by the changes taking effect July 1, 2002). The policy statement said that, if a ship has an approved ECDIS installed according to SOLAS, Chapter V, the ECDIS will be considered as meeting the ship's nautical chart carriage regulations. The ships that are affected are:
    • U.S.-flagged ships of 150 or more gross tons that engage on international voyages.
    • U.S.-flagged ships certificated solely for service on the Great Lakes and the St. Lawrence River.
    • Foreign-flag ships to which SOLAS, Chapter V, applies that are operating on the navigable waters of the United States.
This policy is not applicable to U.S.-flag ships engaged only on domestic voyages. These ships must continue to comply with existing navigation equipment requirements until the chart carriage regulations are formally amended.

furthermore

The International Maritime Organization mandates the use of GPS or some type of electronic navigation system onboard oceangoing ships, but makes no such requirement for celestial navigation equipmen

Watchkeeping code requires deck officers to show proficiency in celestial navigation — but SOLAS (International Convention for the Safety of Life At Sea) doesn’t require ships to carry a sextant!
I am well aware of what the carriage requirements are. Nowhere did I say that we are required, by law, to have the equipment and pubs.

My point is that, in practice, I have yet to work on a ship that did not have a sextant and all of the pubs required to navigate celestially, if necessary. I have also yet to sail on a ship where celestial sights (azimuths and amplitudes) are not the primary means of checking for any compass error. It is done at least once per day, weather permitting. Now, shooting sunlines and all that jazz is pretty much a thing of the past, unless you feel like doing it for fun. But to say that celestial is dead on ocean-going ships because the IMO or USCG says it is, is inaccurate and not the true reality, for now.

I have sailed ships that fully meet the legal requirements for the ECDIS to replace paper charts. That doesn't mean that we stopped correcting the paper charts, didn't make a DR plot, quit laying tracklines and didn't bother to plot fixes using all available means when in pilotage waters. It was business as usual, with another tool thrown in the mix.

Like in many other industries, the regulations don't always match the best practice or real-world practicality (in fact, they rarely do). Company policies and individual Masters (along with common sense!) often demand more. There are a LOT of things we do (and equip ourselves with) on a ship that exceed the regulations because it is considered a best-practice.

Now, as for what the U.S. Navy and merchant ships from other countries do, I step aside - not my area of work.

EDIT: To clarify in my earlier post, my reference to the "required" pubs was meant as in "required to calculate" not, "required by law".
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Old 05-03-2010, 00:48   #209
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It's one thing to have the learning, the tools and choosing, for any number of reasons, not to use them. Not having the learning and or lacking the equipment is an entirely different story. Electronics can and sometimes do go to hell, especially on small boats, (yachts), where there isn't the depth of redundency found elsewhere.

Finding ones position electronically, with a GPS, is certainly quicker and likely more accurate than via sextant shots and messing about with tables and plotting sheets, however should the electronics go down, an estimated position that's within say 5 NM of where one is, is a whole lot better than nothing I suspect.

Also, speaking personally, and I realize that there is no accounting for taste, I find old fashioned sextant navigation (position finding) to be an interesting intellectual exercise. It also serves to keep the kid out of those smokey pool rooms, assuming that any still exist.
Agreed, with every point. I just wanted to clarify that the notion that celestial is dead on ocean-going ships is not entirely accurate.

I also enjoy celestial navigation. It was one thing to learn it in a classroom, but I never really understood it until I actually did it for real. It's definitely one of the more nostalgic things you can do on a modern ship these days.
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Old 05-03-2010, 01:05   #210
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I am well aware of what the carriage requirements are. Nowhere did I say that we are required, by law, to have the equipment and pubs.

My point is that, in practice, I have yet to work on a ship that did not have a sextant and all of the pubs required to navigate celestially, if necessary. I have also yet to sail on a ship where celestial sights (azimuths and amplitudes) are not the primary means of checking for any compass error. It is done at least once per day, weather permitting. Now, shooting sunlines and all that jazz is pretty much a thing of the past, unless you feel like doing it for fun. But to say that celestial is dead on ocean-going ships because the IMO or USCG says it is, is inaccurate and not the true reality, for now.

I have sailed ships that fully meet the legal requirements for the ECDIS to replace paper charts. That doesn't mean that we stopped correcting the paper charts, didn't make a DR plot, quit laying tracklines and didn't bother to plot fixes using all available means when in pilotage waters. It was business as usual, with another tool thrown in the mix.

Like in many other industries, the regulations don't always match the best practice or real-world practicality (in fact, they rarely do). Company policies and individual Masters (along with common sense!) often demand more. There are a LOT of things we do (and equip ourselves with) on a ship that exceed the regulations because it is considered a best-practice.

Now, as for what the U.S. Navy and merchant ships from other countries do, I step aside - not my area of work.

EDIT: To clarify in my earlier post, my reference to the "required" pubs was meant as in "required to calculate" not, "required by law".
Absolutely correct, and very well put sir....

Might i also add, all the god's at the IMO did, simplisticly speaking here, was to remove the word "Sextant" and replace it with "Other", in other words you must have an "Other" means of determining your position....

At no time did they state that a Sextant need not be carried, you will not find that wording or similar anywhere....

I picked a new build up in Singapore last October, and she was still fitted out with a new Sextant and all the relevent tables and publications....

All the above aside, if you want to work in commercial shipping as a Deck Officer, you will still have to learn Celestial Nav and be examined to prove you are proficiant, if you fail then no ticket no job, very simple....

This is still the case here in Aus and most of the shipping nations of the world....
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